Certain devices require a periodic reciprocating motion supplied by an outside motor. A rotational motor (powered by heat or electricity, for example) may generate a periodic rotational motion around a fixed axis, which—when combined with a crankshaft—may be converted to a periodic reciprocating motion. The periodic reciprocating motion, supplied from the rotational motor to the external device, may be defined by a number of characteristics. For example, the frequency of the periodic rotational motion may be determined by the force exerted by the rotational motor. Separately, the amplitude of the periodic reciprocating motion may be determined by the geometry of the crankshaft structure. The skilled artisan will recognize that the force required to maintain the ideal periodic reciprocating motion for any specific need will depend, inter alia, on the mass of the object affected by the device, the amplitude of the periodic reciprocating motion and the frequency of the periodic rotational motion. Therefore, it is advantageous to have a motor with adjustable amplitude and frequency as needed for various external devices and particular tasks. Electric motors with tunable amplitudes and frequencies are known in the art. Examples include pneumatic motors, piezoelectric motors, and electro-magnetic voice coil motors.
One problem that arises in the art is providing a range of both frequencies and amplitudes in a single motor. Motors known in the art typically provide more of one and less of the other. For example, pneumatic motors, which convert compressed air to mechanical energy through either linear or rotary motion, may provide a wide amplitude range, including very high amplitudes. However, pneumatic motors have a limited frequency range and a comparatively low maximum frequency. At the other end of the spectrum, piezoelectric motors, which employ a material that can change dimension when a voltage is applied to the material, may provide a broad frequency range, including very high frequencies. However, piezoelectric motors have a limited amplitude range and a comparatively low maximum amplitude.
Another problem that arises in the art is providing independently adjustable frequencies and amplitudes through means that do not restrict each other. Electro-magnetic voice coil (or solenoid) motors, which combine an electrical coil wound around a cylindrical core with a polarized piston, may provide a wide amplitude range as well as a wide frequency range. However, the means of adjusting either the amplitude or frequency of an electro-magnetic voice coil motor inversely affects the other. Thus, as the frequency increases, the amplitude of the periodic reciprocating motion decreases, and vice versa.
Accordingly, it is an object of the invention to provide a motor with a wide amplitude range as well as a wide frequency range. Another objective of the invention is to provide a motor with independently adjustable frequency and amplitude, such that the decrease or increase of one does not affect or limit the other.